An Iranian military helicopter flies over Revolutionary Guards' fast boats during naval exercises in the Gulf on April 22, 2010. / Mehdi Marizad, AFP/Getty Images

by Oren Dorell, USA TODAY

by Oren Dorell, USA TODAY

Iranian warships headed to the U.S. coast pose little danger to the United States but could be a dry run for the future, according to former U.S. military and security officials.

The mission shows the danger Iran would pose if it possessed nuclear weapons, says John Bolton, a former U.S. ambassador to the United Nations under President George W. Bush and an arms negotiator during the Cold War.

"It shows they could put a weapon on a boat or freighter, and if (Iran) has ballistic missiles it could put it anywhere on the U.S. coast," Bolton said. "Down the road it could be a threat."

Chris Harmer, an analyst at the Institute for the Study of War and a former military planner for the U.S. Navy in Persian Gulf, said one of the two ships is a military cargo ship that has visited China in the past and is suspected of delivering Iranian arms shipments to Sudan on multiple visits to that country in the past few years.

While it poses no tactical threat to the United States, Iran will likely use it to advance its relationship with its ally Venezuela, a U.S. adversary in the Caribbean.

The commander of Iran's Northern Navy Fleet, Adm. Afshin Rezayee Haddad, said Iran sent "a fleet" to the Atlantic Ocean, to approach U.S. maritime borders for the first time, according to the Associated Press, which cited Iran's official IRNA news agency Saturday. The U.S. maritime border is about 14 miles from land.

The news comes as the United States and other world powers prepare to meet Feb. 18 with Iranian diplomats in Vienna to seek a comprehensive agreement about Iran's disputed nuclear program. Iran seeks an agreement that would eliminate economic sanctions over its nuclear program that have crippled its economy. The United States seeks to prevent Iran from developing nuclear weapons.

Iran says its nuclear program has peaceful aims, though the United Nations nuclear watchdog agency says Iran has yet to explain evidence that it designed nuclear warheads and tested nuclear detonators. Iran has among the world's largest supplies of oil and gas for energy.

On Monday, the vessels had begun sailing to the Atlantic Ocean by waters near South Africa, Iran's Fars News Agency reported. Iranian officials last month said the fleet would embark on a three-month mission and consist of a destroyer and a ship that can carry helicopters.

The voyage is part of Iran's response to Washington's beefed up naval presence in the Persian Gulf, according to Fars. The U.S. Navy's 5th fleet is based in Bahrain - across the Persian Gulf from Iran - and the U.S. has conducted two major naval war games in the last two years.

Gary Samore, a former adviser to President Obama on arms control, weapons of mass destruction and terrorism, said Iran has consistently objected to the U.S. military presence in the Persian Gulf.

"Their position is there should be no military bases or forces in the Gulf controlled by countries (that are) not Gulf countries," Samore said. "They say this because if there were no outside powers, Iran would be the strongest power in the region. So it's in their interest to demand there be no external force in the Gulf."

Iran's military doctrine is based on asymmetric warfare, relying on a multilayered strategy the employs many kinds of low-tech weapons and a willingness to accept casualties, says Michael Connell, director of Iranian Studies at the Center for Naval Analyses, which conducts research and analysis for the U.S. government.

In the Persian Gulf, Iran hopes to employ dozens of midget submarines, land-based missile launchers and speedboats, in a strategy meant to confuse and overwhelm an adversary with superior technology and firepower, Connell wrote in an assessment of Iran's naval doctrine.

The ships crossing the Atlantic are an Iranian destroyer, which is the size of a small American frigate and equipped with anti-ship cruise missiles, and a logistics ship, Connell said.

"If they make it to the North Atlantic, and that's a big if - they've never been that far - the threat they pose is minimal," Connell said. "They are not really equipped to threaten land-based targets."

And the vessels would be highly vulnerable, especially to U.S. naval aircraft, he said. "Essentially, they would be at the bottom of the ocean in fairly short order if they assumed a threatening posture."

Bolton said Iran's ships may not pose much of a threat now but their mission shows the Islamic Republic is building up its capabilities for the future. Iranian oil is mostly shipped by foreign tankers.

Iran rarely has sent its own ships outside the Persian Gulf, but is now training ship captains on sailing the Suez canal and the North Atlantic to show their potential reach is far from Iran, Bolton said.

"They are showing they can sail from Iran across the Atlantic Ocean and travel right up to our coast," Bolton said. "They're building up capabilities. That's what training missions do."